The common method for underwater lighting applications such as spas and hot tubs uses 12-volt incandescent light bulbs encased in molded plastic water-sealed housings. The housings are mounted below the spa water level. This provides an attractive coloured glow to the tubs when in operation. It also provides an added safety measure on tub entry and exit. For mood lighting, manufacturers include snap-on lenses in red and blue tints, for example, to alter the appearance and effect of the spa lighting.
Conventional spa lighting applications such as that described above are associated with specific disadvantages. In this regard, there are some problems with the reliability of such systems. The incandescent bulbs frequently fail during the typical 3-year warrantee period of the tubs. The failure of the 12-volt incandescent light bulbs is primarily due to a couple of factors. These small bulbs are commonly rated for about 1000 hours of operational life. If the lights are in use for only two to three hours per day, the bulb would typically need replacement yearly as a regular spa maintenance procedure. Once initially lighted, the bulb filament is very fragile due to the high temperatures obtained during operation. Even slight jarring or knocking on the bulb housing may dislodge or break the filament, thereby requiring replacement. Also, since incandescent bulbs convert most of their energy to heat and as little as 10% to light, the temperature inside the plastic housing is considerably higher than the ambient air temperature, further reducing the durability of the bulb. Use of incandescent lighting can result in increased manufacturer expense through replacement and occasional on-site warrantee servicing of a failed system.
Exterior, or perimeter lighting installed on hot tubs is increasing in popularity due to its intrinsic decorative appeal, as well as for safety and security illumination. In conjunction with residential exterior lighting and deck lighting systems, illumination of the exterior of a hot tub can add to the ambiance of an outdoor lighting strategy. Hot tubs and spas are commonly used in the evening hours, past sunset. Accessing the hot tub after dark without outdoor illumination in the area can be difficult. Illumination of the hot tub exterior is an additional benefit of a decorative exterior lighting system. Hazards such as obstacles and steps are diffusely illuminated and much more easily navigated with the addition of lighting to the outside of a hot tub.
Adding illumination to the exterior of a spa can also add to security in a residential area. The typically dark area surrounding a hot tub can be illuminated by an act as a form of security lighting. Exterior spa lighting has previously been approached using incandescent and fibreoptic lighting systems, each of which has advantages and disadvantages. While quite fragile and prone to failure as previously described, incandescent perimeter lighting is an inexpensive and simple method for exterior illumination.
Fibreoptic systems can be expensive, but provide adjustable colour variation and an attractive glow. Fibreoptic systems, though, typically use incandescent or halogen bulbs as source lighting, encased in a lighting source housing installed near the controlling spa pack of the hot tub. Fibreoptic wire bundles are grouped and concentrated into an opening in the light housing. The light source is lensed and concerted on the sheared ends of the fibreoptic bundles and the light transmitted to varying locations around the hot tub. However, fibreoptic systems are inefficient from a power consumption standpoint and also contain fragile bulb filaments operating at elevated temperatures. Mechanically these filaments are prone to failure from shock or jarring of the lighting supply housing, or through failure of the lighting supply cooling fan. Fibreoptic lighting systems contain mechanical filtering systems for color changes, typically involving a color wheel incorporating various tinted filters rotating between the light source and the fibreoptic bundle used to transmit the light.
Color changes are gradual and non-uniform throughout the fibreoptic cable termination points, with the result that not all lighting outputs throughout the hot tub change color in unison. A time interval is required for a color transition to occur throughout the lighting array, with different termination points lighting at different stages of a color transition.
A continuous need exists for advancement of the pertinent art.